Lately on some maps I've noticed when creating a shape with the polygon shape tool it creates an invisible shape which won't be in anyway visible, regardless of opacity settings. After this invisible shape is created all shapes created will no longer be visible. Pre-existing shapes will still be visible.

After a reload all shapes will be visible.

It also freezes all images on the page.

This only happens sometimes with specific maps so far, other maps have been unaffected. My browser is chrome and it is up to day